We towed my Wife's Honda Accord but it being 13 years old she decided that she needed a newer car so we found a 2013 Ford Edge with only 5000 miles. The manual says to start, run for 5 min, run thru gears, neutral and then turn it off and then to Acc. Why turn it to Accessory? Some people disconnect the battery to keep from running down their battery so what's the...